1. Field of the Invention
The invention relates to medical engineering applied in orthopedics and traumatology and has particular reference to distraction apparatus for plastic reconstruction of the hand.
2. Description of the Related Art
Congenital adactyly or digital hypoplasia, as well as morbid conditions secondary to an injury to digits, are one of the most urgent problems of surgery of the hand. This is concerned with the fact that the hand plays an immense part in human activities. Thus, lack of fingers or underdeveloped hand inflict not only moral but also physical distress upon a patient. Such a person proves to be most frequently not only disabled from any industrial work but cannot also perform self-servicing to provide his/her activities in everyday life.
Attempts made for formation of fingers and plastic reconstruction of the hand using transplants, intra-and extraosseous fixation means in clinical practice have proved to be ineffective, since it is impossible to provide a sufficient amount of soft tissues for simultaneous loading of the transplant and formation of digits. Fixation methods and means for their practical application are imperfect due to their being unreliable and causative of a traumatic lesion.
Apparatus for external fixation of injured bones prove to be a more efficacious means for solving the aforesaid problem.
A prior-art apparatus for distraction of dislocations in the metacarpophalangeal and metatarsophalangeal joints (SU, A, 912,156) is known to comprise traction stirrups carrying fixing pins, pin holders and distraction rods. The stirrups are interconnected to form a closed frame whose opposite sides carry the distraction rods arranged in a row and mounting the fixing pins provided with thrust flats.
The apparatus is capable of differentiated reduction of multiple inveterate disclocations of the metacarophalengeal and metatarsophalangeal joints. Reduction of the 2nd, 3rd, 4th and 5th metacarpophalangeal joints is carried out by alternate distraction with the aid of a pair of distraction rods that lock one pin guided through the respective bones. However, the given construction of the apparatus fails to provide simultaneous stretching out of the bones and plastic reconstruction of the hand. In addition, passing of the pins with thrust flats in the dorsipalmar direction is fraught with considerable traumatic lesion of the tendons and ligaments.
Known in the art presently is a distraction apparatus (SU, A, 1,237,189), comprising supports carrying pins fitted in pin clamps, distraction rods interconnecting the supports, one of which is shaped as an oval structure having holes, wherein U-shaped pins are held with the aid of pin clamps.
The aforesaid distraction apparatus provides access to the surface of the digital segment being stretched out. However, the pins secured on the side cylindrical surface of one of the supports fail to stretch out each of the digital segments separately; besides, soft tissues are liable to be cut through by the U-shaped pins in the course of stretching-out when securing the pins to the bone involved.
Another heretofore-known external fixation apparatus is essentially a more perfect one (cf. Proceedings of the Second International Symposium on Improvements of apparatus and methods for external fixation, vol. I, 1985, Riga, `Improvement in treatment of fractures-dislocations of the anterior and middle foot segments using an external fixation apparatus` by V. V. Klyuchevsky et al., pp. 184-186 (in Russian). The apparatus comprises three semirings and two threaded rods. Two fixing pins are secured in the proximal semiring, while several distraction pins are held in the distal semiring by means of brackets. The semirings are interconnected through two threaded rods.
The aforesaid external fixation apparatus is used for treatment of fractures-dislocations in the Lisfranc's and Chopart's joints. However, the aforesaid apparatus features the fixing pins secured on the distal support with a possibility of performing once-through distraction by drawing up the pins manually. Besides, the pins are held to the distal support at an angle to the connecting threaded rods, which is necessary for treatment of fractures-dislocations of the plantar arch bones, whereas such an arrangement of the apparatus is not adapted for plastic reconstruction of the hand. Spin passage at an angle to the connecting threaded rods and to the longitudinal axis of the bone prevents the distal stump end from being invaginated into the soft-tissue digital rudiment.